A comprehensive review on rice proteins: composition, structural modification, functional and industrial food applications

By-products of the rice processing industry are increasingly recognized as valuable sources of plant-based proteins and bioactive peptides, driven by the growing demand for sustainable protein alternatives. Rice protein is especially promising due to its balanced amino acid profile, high biological value, and low allergenicity, making it ideal for infants, vegans, and those with gluten intolerance. Despite their abundance, the use of these protein-rich by-products in food formulations remains limited, highlighting untapped potential in the food industry. The limited application of native rice protein in food systems is mainly due to its poor water solubility, caused by strong intermolecular interactions, including aggregated sulfhydryl and disulfide bonds. These structural features hinder its functional properties. Novel modification techniques, particularly when combined with enzymatic modification, offer promising strategies to alter its native structure and enhance functionality, thereby broadening its use in diverse food applications. This review provides a comprehensive overview of rice proteins from industrial by-products, detailing their nutritional profile, chemical properties, and isolation methods. It further examines novel structural modification techniques to enhance solubility and functionality. Finally, the review highlights the industrial potential of modified rice proteins in developing value-added and sustainable products for food and nutraceutical applications.